1. Field of the Invention
The present invention relates to electrical wiring systems and more particularly to an electrical wiring system in which a plurality of automobile electrical devices and instruction switches for operating the electrical devices are interconnected through two power supply lines and a single signal line.
2. Description of the Prior Art
In conventional electrical wiring systems for automobiles, as many separate electrical wires as there are loads or electrical devices are required to transmit power between the electrical devices and the associated instruction switches. Consequently, a large number of heavy power transmission wires must be used thus not only increasing the cost of wiring an automobile, but also increasing the volume of the wires and making it difficult to wire up the various electrical devices in the limited space of the automobile. Another disadvantage is the increased probability of causing short circuits between the electrical devices and the vehicle body.